A whole-genome microarray reveals genetic diversity among <i>Helicobacter pylori</i> strains

TLDR

Helicobacter pylori infects about half the global population and causes a spectrum from gastritis to gastric cancer, with severe disease linked to strains carrying a pathogenicity island, though the basis for this diversity remains unclear. The study aimed to characterize genetic diversity between more and less virulent H. pylori strains. Researchers profiled the genomes of 15 clinical isolates using a whole‑genome H.

Abstract

Helicobacter pylori colonizes the stomach of half of the world's population, causing a wide spectrum of disease ranging from asymptomatic gastritis to ulcers to gastric cancer. Although the basis for these diverse clinical outcomes is not understood, more severe disease is associated with strains harboring a pathogenicity island. To characterize the genetic diversity of more and less virulent strains, we examined the genomic content of 15 H. pylori clinical isolates by using a whole genome H. pylori DNA microarray. We found that a full 22% of H. pylori genes are dispensable in one or more strains, thus defining a minimal functional core of 1281 H. pylori genes. While the core genes encode most metabolic and cellular processes, the strain-specific genes include genes unique to H. pylori , restriction modification genes, transposases, and genes encoding cell surface proteins, which may aid the bacteria under specific circumstances during their long-term infection of genetically diverse hosts. We observed distinct patterns of the strain-specific gene distribution along the chromosome, which may result from different mechanisms of gene acquisition and loss. Among the strain-specific genes, we have found a class of candidate virulence genes identified by their coinheritance with the pathogenicity island.